Kiko Alonso will likely miss his second season in the NFL after tearing his ACL while working out in Oregon, the Buffalo Bills announced Wednesday morning.

Alonso suffered the injury Tuesday, and tests confirmed the Bills' initial fears that the injury was significant."

General manager Doug Whaley said in a statement that Alonso will have surgery in the "near future."

"We feel badly for Kiko because he has worked very hard this offseason in preparation for the upcoming season, but we look forward to his return with his style of play that made him one of the league's outstanding rookies in 2013," Whaley said.

Alonso, a second round pick out of Oregon last year, played every snap for the Bills' defense as the team's middle linebacker in 2013, racking up 159 tackles and four interceptions.

With the addition of veteran middle linebacker Brandon Spikes, a former New England Patriot, the Bills, under new defensive coordinator Jim Schwartz, were planning to move Alonso to weakside linebacker. The Bills signed veteran free agent Keith Rivers to play strongside linebacker, though he has played at weakside linebacker before.

Other options to replace Alonso include Nigel Bradham, a fourth-round pick in 2012, or rookie third-round pick Preston Brown.